The well-known Thompson Seedless or Sultanina variety (unpatented) of grape vine is one of the most extensively planted varieties, its fruit being used for raisins and wine, as well as being a leading table grape. Despite its widespread popularity for table use, the Thompson Seedless grapes have numerous deficiencies for such use. The skin of the grapes of this variety are relatively tender for table grape use and thus are easily damaged in shipment and storage. The skin of grapes of this variety begin to acquire an unattractive brownish color after being in cold storage for 45 to 60 days. The grapes do not attain a large and attractive size unless the vines are girdled or have a growth regulator, such as gibberellin, applied at the proper time during the growing season. At the present time, therefore, table grapes of the Thompson Seedless variety are almost universally from vines which have been girdled or sprayed with gibberellin. A further disadvantage of the Thompson Seedless variety of grapes for table use is that bunches of grapes tend to shatter, particularly when the vines are not girdled or sprayed with a growth regulator.
As with other fruits, a variety of grape vine bearing fruit which ripens substantially earlier or later than the usual variety having the same general characteristics is highly advantageous in that fruit of the earlier or later ripening variety can be marketed at a relatively high price due to the then existing scarcity of other satisfactory fruit of the same type. In many cases, difference of a week in ripening date can contribute significantly to the commercial success of a new variety. In particular, it has been recognized that a variety of grape vine bearing fruit similar to that of the Thompson Seedless, but ripening substantially later, would be highly advantageous. The advantage of such a variety would, of course, be significantly enhanced if the effective length of its harvest season were also extended by superior cold storage characteristics and the ability to remain on the vine for a significant period without deterioration.